Moisture management

Good design principles and strategies to mitigate water damage help preserve good indoor air quality. Moisture enters buildings and building assemblies in four ways: bulk water, capillary water, air-transported moisture and vapor diffusion. In addition to preventing wetting from all four channels, managing moisture is also about promoting drying potential.

This feature requires actions for each type of moisture movement. Properly managing moisture can reduce the health risks of pests, mold and bacterial loads.

Part 1: Healthy Sunlight Exposure

Lighting simulations demonstrate that the following conditions are expected:

a.¹ Spatial daylight autonomy (sDA300,50%) is achieved for at least 55% of regularly occupied space. In other words, at least 55% of the space receives at least 300 lux [28 fc] of sunlight for at least 50% of operating hours each year.

b.¹ Annual sunlight exposure (ASE1000,250) is achieved for no more than 10% of regularly occupied space. In other words, no more than 10% of the area can receive more than 1,000 lux [93 fc] for 250 hours each year.

Part 2: Interior Bulk Water Damage Management

To prevent leaks and water damage, one of the following is installed:

a. Readily-accessible, single-throw manual shut-off (governed or activated per use) or automatic shut-off at point-of-connection for all hard-piped fixtures (such as dishwashers, icemakers, clothes washers).

b. Building-wide plumbing leak detection system.

Part 3: Capillary Water Management

To prevent the wicking of water between porous building materials, one of the following capillary break methods is used:

a. Free-draining spaces (such as between exterior claddings or WRBs in wall assemblies).

b. Non-porous materials (such as closed-cell foams, waterproofing membranes and metal) are used between porous materials, such as “sill sealer” between concrete foundation walls and mud sills of above-grade walls.

Part 4: Wetting by Condensation

To mitigate wetting by condensation from thermal bypasses (thermal bridges and air leaks), the following requirements are met:

a. Continuous air barrier.

Part 5: Dedicated Drying Potential of Assemblies

This requirement is met by one of the following methods:

a. Qualitative vapor profile analysis.

b. WUFI analyses of the exterior building assemblies.

Respiratory

Immune

Lymphatic

Integumentary

	Core & Shell	Tenant Improvement	New Construction
Part 1: Healthy Sunlight Exposure	O	O	O
Part 2: Interior Bulk Water Damage Management	P	O	P
Part 3: Capillary Water Management	P	O	P
Part 4: Wetting by Condensation	P	O	P
Part 5: Dedicated Drying Potential of Assemblies	-	-	-

	Commercial Kitchen	Schools	Multifamily Residential	Restaurant	Retail
Part 1: Healthy Sunlight Exposure	O	O	O	O	O
Part 2: Interior Bulk Water Damage Management	P	P	P	P	O
Part 3: Capillary Water Management	P	P	P	P	O
Part 4: Wetting by Condensation	P	P	P	P	O
Part 5: Dedicated Drying Potential of Assemblies	-	-	-	-	-

Verification Methods Matrix

	Letters of Assurance	Annotated Documents
PART 1 (Design) Healthy Sunlight Exposure		Architectural Drawing
PART 2 (Design) Interior Bulk Water Damage Management	MEP
PART 3 (Design) Capillary Water Management	Architect
PART 4 (Design) Wetting by Condensation	Architect

Show Standard Citations

1

U.S. Green Building Council. LEED v4: Reference Guide for Building Design and Construction. Washington D.C.: U.S. Green Building Council; 2013: 37, 43-44, 541-552, 567, 605, 623, 645-53, 658-61, 682-3, 685-6, 723-4.
12.4.e	USGBC's LEED v4 BD+C EQ Credit: Construction Indoor Air Quality Management Plan requires that absorptive materials stored on-site and installed are protected from moisture damage.

**176**

**U.S. Environmental Protection Agency. Moisture Control Guidance for Building Design, Construction and Maintenance. Washington, DC: U.S. Environmental Protection Agency; Dec 2013. EPA 402-F-13053.**
12.1.c	EPA 402-F-13053 notes to design exterior walls to manage rainwater.
12.1.d	EPA 402-F-13053 advises to consider key elements of moisture behavior, including transport mechanisms such as moisture wicking through porous materials.
12.1.a	EPA 402-F-13053 notes that effectively controlling water intrusion requires directing drain rain and irrigation water away frm the building.
12.1.b	EPA 402-F-13053 notes to design buildings such that the interior floor grade is above the local water table.
12.2.a	EPA 402-F-13053 notes that leaks in pipes or tanks in the plumbing system can release water.
12.2.b	EPA 402-F-13053 notes that moisture problems include leaks in pressurized pipes and vessels in appliances that use water.
12.2.c	EPA 402-F-13053 advises to consider key elements of moisture behavior, including transport mechanisms such as moisture wicking through porous materials.
12.2.d	EPA 402-F-13053 notes to "avoid enclosing wet materials in new construction by protecting moisture-sensitive and porous materials" as part of a comprehensive strategy to control liquid water movement.
12.3.a	EPA 402-F-13053 notes that in low-rise buildings, damp basements and crawlspaces may add water vapor to the air.
12.3.b	EPA 402-F-13053 notes that air that infiltrates the building through air leaks represents one of the largest sources of humidity.
12.3.c	EPA 402-F-13053 notes that condensation may be caused by "excessively high dew point, unusually cold surfaces, or a combination of the two."
12.3.d	EPA 402-F-13053 notes that "oversized cooling systems do not solve humidity control problems—instead, they cause them."
12.4.a	EPA 402-F-13053 advises to use materials able to tolerate repeated wetting and drying in wet areas. The document also notes that particularly in buildings in cold climates, it is important to consider the condensation potential of glazing designs.
12.4.b	EPA 402-F-13053 notes that exterior cladding and other measures can intercept most of the rain water and direct it away from the building.
12.4.c	EPA 402-F-13053 advises to use materials able to tolerate repeated wetting and drying in wet areas.
12.4.d	EPA 402-F-13053 advises to use low-permeability insulating sheathing and interior finishes.

This is a legacy version of the WELL Building Standard. Please check the latest version here.

12. Moisture management